Run results for: Should you cache Intl.DateTimeFormat?

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser: Chrome 131

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 4 months ago

Test name	Executions per second
No caching	39791.9 Ops/sec
With JSON-keyed cache	1561063.1 Ops/sec

Script Preparation code:

FORMAT = { day: '2-digit', month: 'short', year: 'numeric' }
cache = new Map()

Tests:

No caching
const date = new Intl.DateTimeFormat('en-AU', FORMAT).format(new Date())
With JSON-keyed cache
const key = JSON.stringify(FORMAT) let formatter = cache.get(key) if (!formatter) { formatter = new Intl.DateTimeFormat('en-AU', FORMAT) cache.set(key, formatter) } const date = formatter.format(new Date())